[keycloak-user] OAuth 2.0 Extension Grants?

[Alvin Alf]

Sent this in HTMl by accident. Let's try this again.
 
Does Keycloak (4.0 and up) support custom extension grants?
 
Relevant section:
https://tools.ietf.org/html/rfc6749#section-4.5
 
Context:
My company has a legacy api that rolled its own access token protocol. I want to create a custom grant type that uses our legacy token as credentials for the token endpoint.

Thanks in advance,
Al